Micromatic adjustment for worktables



' March 6, 1945. A. SERNA 2,370,882

MICROMATIC ADJUSTMENT FOR WORK TABLES Filed Feb. 18, 1943 Illl ISmaentor attorneys Patented Mar. 6, 1945 MIOROMATIC ADJUSTMENT FOR WORKTABLES Alezr Sern a, Dearborn, Mich. t Application February 18, 1943, Serial No. 476367 or. 90-578) t 14 Claims.

The present invention relates to machine tools and'more particularly, to an adjustable work bed therefor. I I

The primary object of the invention is to provide a traversing feed screw for a work-supportingbedfadaptedto beused with precision machine tools and to provide means forcompensating'forlinaccuracie in the feed screw so that aflpredeter'mined movement of the feed screw as registered on a gauge or indicator thereon will producefa corresponding absolute linear movement of the work table or bed.

Another object of the invention is to provide a feed screw for work beds or tables having a compensating thread which is engagedby a probe arm to correct inaccuracies in thescrew and to facilitate the movement offthe. table or work bed'a predetermined distance in accordance with the distance registered on the feed screw indica tor.

Another objector the invention is toprovide a device as setforth in the; above mentioned objects which maybe usedin the formation of master screws as well as beingemployed as a work ,bed ,or table feedscrewc whereby master screws of absolute accuracy may be produced inexpensively and. in asshort period of time;

Another object of the invention is to provide a feed screw for a work table or the like having a compensating thread in addition to the feed will become apparent'during the course of the 5 following description of the accompanying draw-- ing,wherein r Figure '1 is atop plan view of the device embodying the invention illustrating the application thereof to a linearly movable work bed;

Figure 2 is a longitudinal cross-sectional view of the device shown in-Figure 1' illustrating various parts in detail;

Figure 3 is a-fra gmentary'side elevational view lustrating the manner in which the probe arm is presented thereto; i V V Figure 4 is a vertical cross sectional view taken on Fig. 3 illustrating the manner in which the compensating thread may be. preformed by removing portions thereof to impart v accurate movement to the work table or bed;

Figure 5 is a vertical cross sectional view fur ther illustrating in detail various. structural ele ments interconnecting the screw and work bed; 1

' Figure 6 is a longitudinal cros sectional view of the thread receiving traversing nut; and

Figure? is a fragmentary elevational view of In the drawing wherein for the purpose of il-" lustrating :the invention and" wherein like ref erencecharacters will be employed to designate like parts of the same, the reference character 5 will generally be employed to designate a work bed guide including'end frame members 6 and I connected by side walls 9 and I0 having guide Ways Hand [2 respectively formed on the upper edges thereof and integrally connected with the end walls 6 and l. The above const'ructionmay comprise a machine frame for a vertical precision boring machine or other machine tool and may i be capable of vertical ad ustment to position 0 work supported thereby relative to the machine tool. The ways Hand l2 are providedwith bevelled edges as at l3 and M respectively and are adapted to slidably receive a linearly movable work table [5 having marginal depending ribs [Band I! provided with undercut bevelledwalls' l8'and I9 for slidably engaging the bevelled edges l3and I4 of the ways H and 12. The top surface of the work bed ortable I5 is provided with transversely extending slots 20 having re- 0 duced portions 2| to facilitate the reception of bolts or the like which may be used for bolting the work securely in place upon the face of the work bed or table I5. e

Formed in the end wallst and l are bearin" bosses 22 and 23 for receiving bearing portions 24 and 25 of a feed screw generally indicated by the reference character 26. The bearing portions 24 and 25 are reduced in diameter and are snugly fitted "to eliminate as much as possible endwise motion or play between the bearing bosses22 and 23 with respect to the screw 25;

The feed screw 26-is provided with the usual spiral land-21 for forming screw threads 28 of usualconfiguration and said screw threads 28 of tl1'e-feed-screw and compensatingthread i1- are adapted to receive a traversing nut-ZS-jhav ing a spirally formed thread 36 adapted to extend between the vertical walls of the spiral thread 28. The traversing nut 29 is provided along one wall with a groove 3! for receiving a longitudinal rib 32 formed on the inner Wall of the side frame member ID to prevent rotation of said traversing nut and to cause said nut to be fed along said screw 26 upon rotation thereof. One end of thefeed screw 26 is provided w-itha gauge wheel 31 the-hu f whi h as a t ke ed 1: otherwise secured in place by means of a locking pin 35. A crank handle 36 projects outwardly from the wall of the drum as so that the reed screw 26 may be manually rotated and'the end 4 uations 40 marked or otherwise impressed on the peripheral surface of the graduated whee 33-;

Fastened to the under side of the linearly movd able work table is a bracket plate 4i secured in position by bolts or the like as at'42. A bracketfarin 43 depends from the bracket plate M and is provided at its lower end with a bearing boss in registry with the bearing boss 45 formed integral with the bracket plate. M. Sccured between the bearing bosses- M and 45 is a hinge pintle 46 upon which is swingingly mounted a tubular sleeve 41- having a pair of parallel extending arms 48 formed integral therewith and an arm 46 intermediate the ends of the sleeve 4'5 likewise formed integral therewith and extending at right anglesto the spaced-parallel arms 4%. The free ends of the arms 48 are provided with pins 50' over which is hooked one end ofa. pair of coil springs 5 The opposite ends of the the springs are hooked over pins52 extendfrom opposite sides of the traversing nut 29 whereby said arms will be urged toward said nut. Also formed on the traversing screw 29 is a; pair of oppositely extending projections 53 having; notches 54 cut inwardly thereof for receivinga block 55 having one of its knife edges fulcru ned in said notch 54 and its other knife edge, fulcrumed in a notch 56 formed intermediate the lengthof the arm 46. Said fulcrum blocks 55' are prevented from being displaced by beingurged into engagement with the arm 48 and projections 53 by means of the tension creat dv b the s r gs 5 o h t he ork able. .5 win. r new t e r v s ng nut 29. he ce tun gs 5|. will. b of s h a s and. sha e a 9 nipvide su cie t e s o to maa n hefulcruin blocks 55 in operative relation with the pro: locations-48 and. 3-. As g as h ful rum b k are th s tly eld v p ce t e. cm 49. the bell lever will be held in contact with the profile thread Formed on the outer wall of the spiral feed t read. 2.8. is a mnensa ineth ead 51 the. 136* r e l p tion of whic as a 5 is ada ted to be trimmed or filed as shown in Fig. i to o i e: a s al profile g i e to whichis. p sentcd the curved end 59 of; a, probing pin 66 mounted in an opening 61 in the free swinging an of t fulcru lever Th probingin 66 suitably threaded and, is. provided with a lock; nut 62 to lock the same, in a desired ad,-

position and the upper end 83. of the probe at s po yso al r s ap d to ia litate e. re: eention'of a wrench; or h i e hi e mesmesdius men s- By filing or u tin away the pem neral wa rface .8 a p ede erm d amou t t de ir d. l catiqn h l rum ar 49 may be swung on its hinge pin 46 to move the work table or bed I5 backward or forward with respect to the traversing nut 29 so that for every fractional movement or rotation of the graduated drum 33 there will be an absolute movement of the work bed l5 along the entire length of the feed screw 26. Should the threads of the traversing nut 29 and the threads 28 of the feed screw 26 become worn, portions of the spiral compensating et. plate 64;. may support a hinge pintle 66 between suitable spaced bearing lugs as at 61. Rock- 6 ablymounted on the hinge pin 66 is a sleeve similaz tqthe, sleeve 4'. shown in Figs. 1 to 6 inclusive and said sleeve is provided with spaced parallel arms 68 arranged as similar to, the arms 4 8 I A feed screw 69 is provided with a traversing nut; 76 and the arms 66 are urged toward thetraversing nut 10 bymeans of coil springs or th like,

it fastened over pins 72 and (3 on the, arms 68 and traversing screw 16 respectively; The fulcrum arm 14 is substantially identical to the arm 49 shown in Figs. 1 to 6 and hasits free end similarly provided with a probe pin for engagmg a compensating thread on thefeed screw 66. Secured in suitable recesses intermediate the length of the spaced parallel arms 56 is a hard ened bearing block 16 adapted tobe engaged by a fulcrum ro1leri l received in a circular cutaway portion 18 ina hardened wear block 16 mounted in the traversing nut 76. The oper ation of the fulcrum structure shown in Fig; 7' is substantially identical to the fulcrum structure shown in Figs. 1 to 6 inclusive and is illustrative of other means by which the may be carried out.

It is to be understood that the for-ms of the invention herewith shown and described are to invention V be taken as preferred embodimentsof the same and; that; changes in the shape, size and"ai-' rangement of parts may be resorted to without departing from the. spirit of the invention or the SQQD Q the subjoined claims; i i

Whatl claim is:

1., In combination, a movable support and a support moving member an adjusting device pivuted to said support having an arm thereon, said adjusting; device, being adapted for variably con nesting said movable support. and moving memb r.- and profile means on the moving member ensaeeable y said arm, for varying; the rela, tive movement. between the moving member and movab su p rt throughout the-length of. travel f s d mo able supports 2. In combination, a worksupport and a. feed sc w hav n a p ofile rface fo snoring said support, an adjusting device pivoted to the un--; l rs f said support interconnecting said screw and sup or f r ative movement tbexcbetween and a probe arm. n sa d adjust ng: deviceem gaging said profile surface and controlled, by the move ent f e eeds rew'mrni ving the.- su p r relativelto he. iced severwhere y gu in. said eed screw be ompensated n combi a ion, a mo able were; supp rt and a feed screw therefor haying; a fqr np sur face, an adiust ns de ice. pivoted in sa d suppo t havin an arm thereon, said adjust ng c-r vice being adapted for variably interconnecting said screw with the work support and a probe arm engaging the form surface and controlled by the feed screw for varying said interconnecting means to compensate for inaccuracies in said, 'feed screw.

4. In combination, a work support and a feed screw for moving said support, an adjusting device pivoted to the Work support for variably connecting said screw and support so as to permit movement of said work support a slight distance independently of the movement imparted to the work support by said screw and means carried by said adjusting device controlled by rotation of said feed screw for varying said connection a slight amount tothereby compensate for inaccuracies in the feed screw.

5. In combination, a movable support and a feed screw for moving said support linearly along said screw having a form surface thereon, an adjusting device carried by said movable support pivotally connecting said support with said feed screw and a member extending from said adjusting device engaging said form surface and controlled by the movement of said screw for rocking said pivotal adjusting device and causing a slight relative movement between said support and screw in both directions of support movement as said support is fed bysaid screw.

6. In combination, a work support and a feed screw for moving said support linearly along said support, said feed screw having a profile surface formed on the threads thereof, a bell crank lever carried by the work support, a nonrotatable nut on the feed screw, a pivotal connection between one'arm of said bell crank lever and nut adjustably connecting said bell crank lever and said feed screw to permit a slight movement therebetween, and a. probe member on said other arm of the bell crank lever engaging said profile surface to move said support relative to said nut a slight distance in either of its directions of movement and thereby compensate for inaccuracies in the thread pitch of said screw.

'7. In combination, a linearly movable work support and a feed screw therefor having a travelling nut thereon, a bell crank lever pivoted to the work support having one end fulcrumed on the travelling nut'and its opposite end presented to and controlled by said screw whereby rocking movement thereof will cause relative movement between the work support and screw. 8. In combination, a movable work support and a feed screw therefor having a compensating profile thread portion, a travelling nut on said feed screw, a pivotal connection between said nut and work support and means controlled and nut, and a probe arm carried by said pivotal fulcrum having one end engaging the profile thread for causing relative movement between f the support and travelling nut to compensate for inaccuracies in the feed screw.

additional profile threads, a nut mounted on said screw threads, a pivotal connection between said nut and work support and a probe arm engaging said profile thread for shifting said support relative to said nut to compensate for inaccuracies in the feed screw threads.

11. In combination, a linearly movable work support and an actuator screwtherefor having feed and profile threads, a travelling non-rotatable nut carried by the actuator screw operably engaging said feed threads, a fulcrum member pivotally connecting the nut with the work support and a probe arm carried by the fulcrum member having its end engaging the profile thread while said support will be moved relative to the nut during its movement along the feed threads to compensate for inaccuracies therein.

12. In combination, a movable work support and an actuator screw therefor having spiral inaccuracies in the feed threads of said screw.

by the profile thread for moving said support relative to said nut whereby said support will travel an equal linear distance corresponding to an equal distance of said feed screw. 9. In combination, a movable work s'uppor and a feed screw therefor having a profile comcompensated for.

13. A device of the character described, comprising a movable work table, a screw having feed threads for moving said table, a nut adapted to travel on said feed thread, a profile thread on the feed thread, a fulcrum lever pivoted on the under side of the work table, resilient means for connecting said fulcrum lever to said nut and a probe arm carried by said fulcrum lever engaging said profilethread. for rocking said lever andmoving the work table relative to said nut.

14. A device of'the character described, comprising a linearly movable work table, an actuator screw for moving the work table having feed and configured profile threads, a non-rotatable nut mounted on said screw operably engaging said feed threads, a bell crank lever pivotally mounted on said table, a coil spring connecting one of the arms of said bell crank lever with the nut,fulcrum blocks interposed between the nut and said bell crank arm and a probe carried by the other end of the bell crank lever adapted to engage the configured profile threads whereby inaccuracies in the ALEX SERNA.

feed thread may be 

